Illumination device, electronic apparatus including the same, and illumination method

ABSTRACT

Provided is an illumination device including a display panel including a first surface and a second surface that is opposite to the first surface, the display panel being configured to output light including image information through the first surface, a light source configured to emit light, the light source being spaced apart from the display panel in a direction away from and normal to the second surface of the display panel, a window panel including a first area configured to transmit the light output from the display panel and a second area configured to transmit the light emitted from the light source, and a light transmitting unit provided between the window panel and the light source, the light transmitting unit configured to transmit the light emitted from the light source to an object through the second area, the light transmitting unit including at least one meta-surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/557,393, filed Aug. 30, 2019, which claims the benefit of U.S.Provisional Application No. 62/728,252, filed on Sep. 7, 2018 in theU.S. Patent and Trademark Office, and U.S. Provisional Application No.62/730,281, filed on Sep. 12, 2018 in the U.S. Patent and TrademarkOffice, and priority to Korean Patent Application No. 10-2019-0030559,filed on Mar. 18, 2019 in the Korean Intellectual Property Office, thedisclosures of which are incorporated herein in their entireties byreference.

BACKGROUND 1. Field

Example embodiments of the present disclosure relate to an illuminationdevice, an electronic apparatus including the illumination device, andan illumination method.

2. Description of the Related Art

Technologies for mobile devices such as smartphones equipped withsensors such as proximity sensors, three dimensional (3D) depth sensors,or the like have been developed. To apply such sensors to smartphones,light-emitting devices capable of generating light necessary for sensingare required. In this case, it may be difficult to provide a region inwhich a light-emitting device is provided in a smartphone.

In general, a smartphone includes a display panel to display images.Such a display panel is divided into a plurality of regions on whichon-off control is performed to display images, and such regions arereferred to as display pixels. Display pixels include display elementssuch as light-emitting diodes (LEDs) configured to display images, andcircuit elements configured to control the display elements. Since ametallic material that does not transmit light is included in thecircuit elements, light necessary for sensing operations of sensors maynot pass through the display pixels.

Therefore, a light-emitting device configured to generate lightnecessary for sensing may have to be provided in a region separate fromthe display panel. In this case, however, the size of a smartphone mayincrease because an area other than the display panel is required.Alternatively, a notch may be formed in a region of a display panel toplace a light-emitting device in the notch. However, this may complicatethe design of a display surface of the display panel.

SUMMARY

One or more example embodiments provide an illumination deviceconfigured to output light through an edge portion of a display surfaceof an electronic apparatus, and an electronic apparatus including theillumination device.

One or more example embodiments provide an illumination method ofoutputting light through an edge portion of a display surface of anelectronic apparatus.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the example embodiments.

According to an aspect of an example embodiment, there is provided anillumination device including a display panel including a first surfaceand a second surface that is opposite to the first surface, the displaypanel being configured to output light including image informationthrough the first surface, a light source configured to emit light, thelight source being spaced apart from the display panel in a directionaway from and normal to the second surface of the display panel, awindow panel including a first area configured to transmit the lightoutput from the display panel and a second area configured to transmitthe light emitted from the light source, and a light transmitting unitprovided between the window panel and the light source, the lighttransmitting unit configured to transmit the light emitted from thelight source to an object through the second area, the lighttransmitting unit comprising at least one meta-surface.

The at least one meta-surface of the light transmitting unit may includea first meta-surface configured to deflect the light emitted from thelight source such that the light deflected by the first meta-surface hasa first directivity, a second meta-surface configured to deflect thelight deflected by the first meta-surface and having the firstdirectivity such that the light deflected by the second meta-surface hasa second directivity that is different from the first directivity, and athird meta-surface configured to diffuse the light deflected by thesecond meta-surface.

A center portion of the second meta-surface and a center portion of thethird meta-surface may face the second area in a direction normal to thesecond area.

A center portion of the first meta-surface may be closer to the displaypanel than the center portion of the second meta-surface is to thedisplay panel.

The first directivity may correspond to a direction from the centerportion of the first meta-surface toward the center portion of thesecond meta-surface.

The second directivity may correspond to a direction from the centerportion of the second meta-surface toward the center portion of thethird meta-surface.

The second directivity may be equal to a direction in which the lightemitted from the light source propagates toward the first meta-surface.

The light transmitting unit may further include a first substrateprovided between the first meta-surface and the second meta-surface, anda second substrate provided between the second meta-surface and thethird meta-surface.

The first meta-surface may include a plurality of first nanostructureshaving a shape dimension which is less than a wavelength of the lightemitted from the light source.

The first meta-surface may be configured to collimate the light emittedfrom the light source based on a shape and a distribution of each of theplurality of first nanostructures.

The second meta-surface may include a plurality of second nanostructureshaving a shape dimension which is less than a wavelength of the lightfrom the light source.

The second meta-surface may be configured to collimate the light outputfrom the first meta-surface based on a shape and a distribution of eachof the plurality of second nanostructures.

The third meta-surface may include a plurality of third nanostructureshaving a shape dimension which is less than a wavelength of the lightfrom the light source.

The third meta-surface may be configured to diffuse and transmit thelight output from the second meta-surface to radiate the object withflood illumination based on a shape and a distribution of each of theplurality of third nanostructures.

The flood illumination may have a field of view of 80 degrees.

The light source may include a plurality of light-emitting elements.

Each of the plurality of light-emitting elements may include a verticalcavity surface emitting laser (VCSEL).

The illumination device may further include a support substrate providedon a lower side of the light source opposite to the light transmittingunit, a plurality of support portions provided between the supportsubstrate and the light transmitting unit and configured to provide aspace in which the light source is provided, and a housing surroundingthe window panel, the light transmitting unit, the support substrate,and the plurality of support portions.

According to another aspect of an example embodiment, there is providedan electronic apparatus including an illumination device including adisplay panel including a first surface and a second surface that isopposite to the first surface, the display panel being configured tooutput light including image information through the first surface, alight source configured to emit light, the light source being spacedapart from the display panel in a direction away from and normal to thesecond surface of the display panel, a window panel including a firstarea configured to transmit the light output from the display panel anda second area configured to transmit the light emitted from the lightsource, and a light transmitting unit provided between the window paneland the light source, the light transmitting unit configured to transmitthe light emitted from the light source to an object through the secondarea, the light transmitting unit comprising at least one meta-surface,a sensor configured to receive light reflected from the object, and aprocessor configured to acquire information about the object based onthe light received by the sensor.

According to yet another aspect of an example embodiment, there isprovided an illumination method using an illumination device, theillumination device including a window panel having a first area and asecond area, and a light source provided on a lower side of an area notcorresponding to the second area, the illumination method includingrefracting light emitted from the light source to change a direction ofthe light emitted by the light source toward a lower surface of thesecond area, refracting and collimating the light incident on the lowersurface of the second area to change the direction of the light incidenton the lower surface of the second area toward a lower surface of thewindow panel, and diffusing the light incident on the lower surface ofthe window panel to emit flood illumination light.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or other aspects will become apparent and more readilyappreciated from the following description of example embodiments, takenin conjunction with the accompanying drawings in which:

FIG. 1 is a side cross-sectional view illustrating an illuminationdevice according to an example embodiment;

FIG. 2 is a side cross-sectional view illustrating a state in which thepropagation direction of light is changed by a light transmitting unitshown in FIG. 1 ;

FIG. 3 is an example side cross-sectional view illustrating a lighttransmitting unit according to an example embodiment;

FIG. 4 is an example side cross-sectional view illustrating a lighttransmitting unit according to an example embodiment;

FIG. 5 is a side cross-sectional view illustrating a state in which thepropagation direction of light is changed by a light transmitting unitaccording to an example embodiment;

FIG. 6 is a view illustrating a simulation of flood illumination by theillumination device shown in FIG. 1 ;

FIG. 7 is a block diagram illustrating a configuration of an electronicapparatus according to an example embodiment;

FIG. 8 is a perspective view illustrating an example appearance of theelectronic apparatus shown in FIG. 7 ; and

FIG. 9 is a flowchart illustrating an illumination method according toan example embodiment.

DETAILED DESCRIPTION

Reference will now be made in detail to example embodiments of which areillustrated in the accompanying drawings, wherein like referencenumerals refer to like elements throughout, and the size or thickness ofeach element may be exaggerated for clarity of illustration. In thisregard, the example embodiments may have different forms and should notbe construed as being limited to the descriptions set forth herein.Accordingly, the example embodiments are merely described below, byreferring to the figures, to explain aspects. Expressions such as “atleast one of,” when preceding a list of elements, modify the entire listof elements and do not modify the individual elements of the list. Forexample, the expression, “at least one of a, b, and c,” should beunderstood as including only a, only b, only c, both a and b, both a andc, both b and c, or all of a, b, and c.

It will be understood that although the terms “first,” “second,” etc.may be used herein to describe various elements, these elements shouldnot be limited by these terms. These terms are only used to distinguishone element from other elements.

In the following description, when an element is referred to as being“above” or “on” another element, it may be directly on the other elementwhile making contact with the other element or may be above the otherelement without making contact with the other element.

In the present disclosure, it will be further understood that the terms“comprises” and/or “comprising” specify the presence of stated featuresor elements, but do not preclude the presence or addition of one or moreother features or elements.

FIG. 1 is a side cross-sectional view illustrating an illuminationdevice 1000 according to an example embodiment. FIG. 2 is a sidecross-sectional view illustrating a state in which the propagationdirection of light is changed by a light transmitting unit 400 shown inFIG. 1 .

Referring to FIG. 1 , the illumination device 1000 may include a displaypanel 100 having a first surface 100 a and a second surface 100 b thatface each other, the display panel 100 being configured to output lighthaving image information through the first surface 100 a, a light source200 spaced apart from the display panel 100 in a direction away from thesecond surface 100 b of the display panel 100, a window panel 300including a first area A1 transmitting light output from the displaypanel 100 and a second area A2 transmitting light emitted from the lightsource 200, and the light transmitting unit 400 arranged between thewindow panel 300 and the light source 200 and transmitting light emittedfrom the light source 200 to an object through the second area A2, thelight transmitting unit 400 including at least one meta-surface. Inaddition, the illumination device 1000 may further include a supportsubstrate 500 provided on a lower side of the light source 200, aplurality of support portions, for example, a first support portion 610and a second support portion 620 provided between the support substrate500 and the light transmitting unit 400 to ensure a space in which thelight source 200 is provided, and a housing 700 surrounding the windowpanel 300, the light transmitting unit 400, the support substrate 500,and the second support portion 620.

The display panel 100 may include the first surface 100 a through whichlight having image information is output, and the second surface 100 bopposite to the first surface 100 a, wherein a plurality of displaypixels may be arranged between the first surface 100 a and the secondsurface 100 b.

The display panel 100 may include a display element such as a liquidcrystal display (LCD) or an organic light-emitting diode (OLED). Whenthe display element is an LCD, the display panel 100 may be providedwith a separate light source for the display element. The displayelement is divided into a plurality of regions on which on-off controlis performed according to image information, and the regions may bedisplay pixels.

The light source 200 may be a light-emitting array including a pluralityof light-emitting elements 220 and a substrate 210. For example, thelight-emitting elements 220 may be LEDs or laser diodes configured toemit laser light. The light-emitting elements 220 may be vertical cavitysurface emitting lasers (VCSELs). The light-emitting elements 220 may bedistributed feedback (DFB) lasers. For example, each of thelight-emitting elements 220 may include an active layer that has a III-Vgroup semiconductor material or a II-VI group semiconductor material anda multi-quantum well structure. However, the light-emitting elements 220are not limited thereto. The light-emitting elements 220 may emit laserlight having a wavelength of about 850 nm or about 940 nm, or may emitlight in a near infrared wavelength band or a visible light wavelengthband. The wavelength of light emitted from the light-emitting elements220 is not particularly limited, and the light-emitting elements 220 maybe configured to emit light in a desired wavelength band.

The window panel 300 may include a material that transmits light. Forexample, the window panel 300 may include, but is not limited to, glass.The display panel 100 may be provided on the window panel 300 in thefirst area A1 of the window panel 300. Thus, light output from thedisplay panel 100 may pass through the first area A1. The first area A1may be a center portion of the window panel 300. The display panel 100is not provided in the second area A2. For example, the lighttransmitting unit 400 may be provided in the second area A2. As aresult, light emitted from the light source 200 and passing through thelight transmitting unit 400 may propagate through the second area A2.The second area A2 may be an edge portion of the window panel 300.

The light transmitting unit 400 may be arranged between the window panel300 and the light source 200, and may transmit light emitted from thelight source 200 to an object through the second area A2. The lighttransmitting unit 400 may include a first meta-surface 410 that deflectslight emitted from the light source 200 such that the light may have afirst directivity. The light transmitting unit 400 may include a secondmeta-surface 420 that deflects the light deflected by the firstmeta-surface 410 and having the first directivity such that the lightmay have a second directivity different from the first directivity. Thesecond meta-surface 420 may be provided between the first meta-surface410 and the window panel 300. The light transmitting unit 400 mayinclude a third meta-surface 430 which diffuses the light deflected bythe second meta-surface 420. The third meta-surface 430 may be providedbetween the second meta-surface 420 and the window panel 300. A centerportion of the second meta-surface 420 and a center portion of the thirdmeta-surface 430 may face the second area A2. However, exampleembodiments are not limited thereto. For example, a central portion ofthe first meta-surface 410 may face the first area A1. Accordingly, acenter portion of the first meta-surface 410 may be closer to thedisplay panel 100 than the center portion of the second meta-surface 420is to the display panel 100. The first meta-surface 410 faces the lightsource 200 in a direction normal to the first meta-surface 410, and thusit is difficult to arrange the light source 200 to face the second areaA2 in a direction normal to the second area A2 because of designlimitations. As described above, the light transmitting unit 400 maychange the propagation direction of light emitted from the light source200 that does not face the second area A2 in a direction normal to thesecond area A2 such that the light may be incident on the second area A2in a direction normal to the second area A2. The process in which thepropagation direction of light emitted from the light source 200 ischanged by the light transmitting unit 400 will be described later withreference to FIG. 2 .

In addition, the light transmitting unit 400 may include a firstsubstrate 440 between the first meta-surface 410 and the secondmeta-surface 420. The light transmitting unit 400 may include a secondsubstrate 450 between the second meta-surface 420 and the thirdmeta-surface 430. The first substrate 440 and the second substrate 450may be paths through which light emitted from the light source 200propagates. For example, the first substrate 440 and the secondsubstrate 450 may include, but are not limited thereto, glass configuredto transmit light.

The distance between the light transmitting unit 400 and the windowpanel 300 may be less than the distance between the light transmittingunit 400 and the light source 200. For example, the distance between thewindow panel 300 and the third meta-surface 430 facing the second areaA2 may be less than the distance between the first meta-surface 410 andthe light source 200.

Referring to FIG. 2 , the light transmitting unit 400 may include thefirst substrate 440, the first meta-surface 410 and the secondmeta-surface 420 provided on opposite sides of the first substrate 440,the second substrate 450 provided on the second meta-surface 420, andthe third meta-surface 430 provided on the second substrate 450. Thefirst meta-surface 410 and the second meta-surface 420 may not face eachother in a direction normal to the first meta-surface 410 and the secondmeta-surface 420 with the first substrate 440 therebetween. The thirdmeta-surface 430 and the second meta-surface 420 may face each otherwith the second substrate 450 therebetween. Light coming from the lightsource 200 may be incident on the first meta-surface 410. The firstmeta-surface 410 may deflect the light emitted from the light source 200such that the light may have a first directivity. For example, the firstmeta-surface 410 may refract light emitted from the light source 200such that the light may have a first directivity. Light emitted from theplurality of light-emitting elements 220 may not be uniformly refractedby the first meta-surface 410. The first directivity may indicate adirection toward the center portion of the second meta-surface 420 fromthe center portion of the first meta-surface 410. The direction towardthe center portion of the second meta-surface 420 may include adirection exactly toward the center of the second meta-surface 420 and adirection toward the vicinity of a region in which the secondmeta-surface 420 is located. Therefore, light emitted from the lightsource 200 may propagate from the first meta-surface 410 toward thesecond meta-surface 420 by passing through the inside of the firstsubstrate 440. As the light emitted from the light source 200 propagatesfrom the first meta-surface 410 to the second meta-surface 420 asdescribed above, the beam width of the light may increase. For example,the beam width of the light output at the first meta-surface 410 may beless than the beam width of the light incident on the secondmeta-surface 420.

The light deflected by the first meta-surface 410 may be deflected bythe second meta-surface 420 such that the light may have a seconddirectivity. For example, the second meta-surface 420 may refract lightoutput from the first meta-surface 410 such that the light may have asecond directivity. The second directivity may indicate a directiontoward the center portion of the third meta-surface 430 from the centerportion of the second meta-surface 420. The direction toward the centerportion of the third meta-surface 430 may include a direction exactlytoward the center of the third meta-surface 430 and a direction towardthe vicinity of a region in which the third meta-surface 430 is located.Accordingly, the light may propagate toward the third meta-surface 430in a direction normal to the third meta-surface 430. In addition, thesecond directivity may be the same as the direction in which lightpropagates from the light source 200 toward the first meta-surface 410.In addition, the second meta-surface 420 may simultaneously refract andcollimate the light output from the first meta-surface 410. Accordingly,the light output from the first meta-surface 410 may be collimated bythe second meta-surface 420, and then the light may proceed toward thethird meta-surface 430 as parallel light.

The light deflected by the second meta-surface 420 may be diffused bythe third meta-surface 430. The light diffused by the third meta-surface430 may be transmitted to an object located outside the illuminationdevice 1000 as flood illumination light. The field of view of the floodillumination formed by the third meta-surface 430 may be about 80degrees, but is not limited thereto.

The first meta-surface 410, the second meta-surface 420, and the thirdmeta-surface 430 may respectively include a plurality of firstnanostructures 10, a plurality of second nanostructure 20, and aplurality of third nanostructures 30 which have a shape dimension lessthan the wavelength of light emitted from the light source 200. Forexample, the thickness or width of the first nanostructure 10, thesecond nanostructure 20, and third nanostructure 30, which defines theshape of the first nanostructure 10, the second nanostructure 20, andthird nanostructure 30, may be less than the wavelength of light emittedfrom the light source 200. The first nanostructure 10, the secondnanostructure 20, and third nanostructure 30 may have various shapessuch as a cylinder shape, an elliptic cylinder shape, or a polygonalcylinder shape. The first nanostructure 10, the second nanostructure 20,and third nanostructure 30 may respectively include a material having arefractive index greater than the refractive index of a surroundingmaterial, for example, air, or the refractive index of the firstsubstrate 440 and the second substrate 450. For example, the firstnanostructure 10, the second nanostructure 20, and third nanostructure30 may include one of single crystal silicon (Si), poly Si, amorphousSi, silicon nitride (Si₃N₄), gallium phosphide (GaP), titanium oxide(TiO₂), aluminum antimonide (AlSb), aluminum arsenide (AlAs), aluminumgallium arsenide (AlGaAs), aluminum gallium indium phosphide (AlGaInP),boron phosphide (BP), and zinc germanium phosphide (ZnGeP₂).

The first nanostructure 10, the second nanostructure 20, and thirdnanostructure 30 may change the propagation direction of incident lightdepending on factors such as the shape or arrangement of the firstnanostructure 10, the second nanostructure 20, and third nanostructure30. For example, the shape distribution of the first nanostructures 10may be determined such that the first meta-surface 410 may refract lightemitted from the light source 200. In addition, the shape distributionof the second nanostructures 20 may be determined such that the secondmeta-surface 420 may refract and collimate light output from the firstmeta-surface 410. In addition, the shape distribution of the thirdnanostructures 30 may be determined such that the third meta-surface 430may diffuse light coming from the second meta-surface 420. Here, theshape distribution may include the shape and size of the firstnanostructure 10, the second nanostructure 20, and third nanostructure30. In addition, the shape distribution may include the distribution ofthe arrangement pitches of the first nanostructure 10, the secondnanostructure 20, and third nanostructure 30. Accordingly, one or moreof the thickness, the width, and the arrangement interval of the firstnanostructure 10, the second nanostructure 20, and third nanostructure30 may be equal to or less than half the wavelength of light emittedfrom the light source 200. In FIG. 2 , the first nanostructure 10, thesecond nanostructure 20, and third nanostructure 30 are illustrated ashaving a constant size and a constant arrangement interval. However,example embodiments are not limited thereto.

The first substrate 440 and the second substrate 450 may support thefirst nanostructure 10, the second nanostructure 20, and thirdnanostructure 30, and may include a material having a refractive indexless than the refractive index of the first nanostructure 10, the secondnanostructure 20, and third nanostructure 30. The difference between therefractive index of the first substrate 440 and the second substrate 450and the refractive index of the first nanostructure 10, the secondnanostructure 20, and third nanostructure 30 may be about 0.5 orgreater. For example, the first substrate 440 and the second substrate450 may include SiO₂, a transparent conductive oxide (TCO), or a polymersuch as polycarbonate (PC), polystyrene (PS), or polymethylmethacrylate(PMMA), but are not limited thereto.

FIG. 3 is an example side cross-sectional view illustrating a lighttransmitting unit 401 according to an example embodiment. FIG. 4 is anexample side cross-sectional view illustrating a light transmitting unit402 according to an example embodiment. In FIGS. 3 and 4 , thepropagation directions of light are simply indicated with arrows. Thearrows indicate only the directivity of light and do not specificallyshow how light actually propagates. The light transmitting unit 401shown in FIG. 3 or the light transmitting unit 402 shown in FIG. 4 mayreplace the light transmitting unit 400 shown in FIG. 1 .

Referring to FIG. 3 , the light transmitting unit 401 may include afirst substrate 441, first meta-surface 411 and second meta-surface 421provided on opposite sides of the first substrate 441, a secondsubstrate 451 provided on a second meta-surface 421, and a thirdmeta-surface 431 provided on the second substrate 451. The firstmeta-surface 411 and the second meta-surface 421 may not face each otherin a direction normal to the first meta-surface 411 and the secondmeta-surface 421 with respect to the first substrate 441 therebetween.The third meta-surface 431 and the second meta-surface 421 may face eachother in a direction normal to the third meta-surface 431 and the secondmeta-surface 421 with the second substrate 451 therebetween. The secondmeta-surface 421 may be provided on the second substrate 451 and spacedapart from the first substrate 441. Accordingly, a gap may be formedbetween the second meta-surface 421 and the first substrate 441. Lighthaving a first directivity output from the first meta-surface 411 maypropagate in the first substrate 441. The first directivity may indicatea direction toward a center portion of the second meta-surface 421 froma center portion of the first meta-surface 411. The direction toward thecenter portion of the second meta-surface 421 may include a directionexactly toward the center of the second meta-surface 421 and a directiontoward the vicinity of a region in which the second meta-surface 421 islocated. The light having the first directivity may pass through thefirst substrate 441 and the gap, and may then be incident on the secondmeta-surface 421. The light incident on the second meta-surface 421 maybe modified to have a second directivity by the second meta-surface 421.The second directivity may indicate a direction toward a center portionof the third meta-surface 431 from the center portion of the secondmeta-surface 421. The direction toward the center portion of the thirdmeta-surface 431 may include a direction exactly toward the center ofthe third meta-surface 431 and a direction toward the vicinity of aregion in which the third meta-surface 431 is located. The light havingthe second directivity may propagate in the second substrate 451. Thelight propagating in the second substrate 451 may be incident on thethird meta-surface 431 in a direction normal to the third meta-surface431 which is provided on the second substrate 451. The light incident onthe third meta-surface 431 may be diffused by the third meta-surface431.

As described above, the first meta-surface 411, the second meta-surface412, and the third meta-surface 431 may respectively have a plurality offirst nanostructures 11, a plurality of second nanostructures 21, and aplurality of third nanostructures 31. The first nanostructure 11, thesecond nanostructure 21, and the third nanostructure 31 may change thepropagation direction of incident light depending on factors such as theshape or arrangement of the first nanostructure 11, the secondnanostructure 21, and the third nanostructure 31. For example, the shapedistribution of the first nanostructures 11 may be determined such thatthe first meta-surface 411 may refract light emitted from a light source201. In addition, the shape distribution of the second nanostructures 21may be determined such that the second meta-surface 421 may refract andcollimate light output from the first meta-surface 411. In addition, theshape distribution of the third nanostructures 31 may be determined suchthat the third meta-surface 431 may diffuse light coming from the secondmeta-surface 421.

Referring to FIG. 4 , the light transmitting unit 402 may include afirst substrate 442, first meta-surface 412 and second meta-surface 422provided on opposite sides of the first substrate 442, a secondsubstrate 452 provided on the second meta-surface 422, and a thirdmeta-surface 432 provided on the second substrate 452. The firstmeta-surface 412 and the second meta-surface 422 may not face each otherin a direction normal to the first meta-surface 412 and the secondmeta-surface 422 with the first substrate 442 therebetween. The thirdmeta-surface 432 and the second meta-surface 422 may face each other ina direction normal to the second meta-surface 422 and the thirdmeta-surface 432 with the second substrate 452 therebetween. The secondmeta-surface 422 may be provided on the first substrate 442 and spacedapart from the second substrate 452. Accordingly, a gap may be formedbetween the second meta-surface 422 and the second substrate 452. Lightrefracted by the first meta-surface 412 and thus having a firstdirectivity may propagate in the first substrate 442. The firstdirectivity may indicate a direction toward a center portion of thesecond meta-surface 422 from a center portion of the first meta-surface412. The direction toward the center portion of the second meta-surface422 may include a direction exactly toward the center of the secondmeta-surface 422 and a direction toward the vicinity of a region inwhich the second meta-surface 422 is located. In addition, the lightpropagating in the first substrate 442 is refracted and collimated bythe second meta-surface 422 and thus has a second directivity, and thenthe light may be incident on the second substrate 452 after passingthrough the gap between the second meta-surface 422 and the secondsubstrate 452. The second directivity may indicate a direction toward acenter portion of the third meta-surface 432 from the center portion ofthe second meta-surface 422. The direction toward the center portion ofthe third meta-surface 432 may include a direction exactly toward thecenter of the third meta-surface 432 and a direction toward the vicinityof a region in which the third meta-surface 432 is located. The Lightincident on the second substrate 452 may propagate in the secondsubstrate 452 and may then be incident on the third meta-surface 432 ina direction normal to the third meta-surface 432 which is provided onthe second substrate 452. The light incident on the third meta-surface432 may be diffused by the third meta-surface 432.

As described above, the first meta-surface 412, the second meta-surface422, and the third meta-surface 432 may respectively have a plurality offirst nanostructures 12, a plurality of second nanostructures 22, and aplurality of third nanostructures 32. As described above, the firstmeta-surface 412, the second meta-surface 422, and the thirdmeta-surface 432 may respectively include a plurality of firstnanostructures 12, a plurality of second nanostructures 22, and aplurality of third nanostructures 32. The first nanostructure 12, thesecond nanostructure 22, and the third nanostructure 32 may change thepropagation direction of incident light depending on factors such as theshape or arrangement of the first nanostructure 12, the secondnanostructure 22, and the third nanostructure 32. For example, the shapedistribution of the first nanostructures 12 may be determined such thatthe first meta-surface 412 may refract light emitted from a light source202. In addition, the shape distribution of the second nanostructures 22may be determined such that the second meta-surface 422 may refract andcollimate light output from the first meta-surface 412. In addition, theshape distribution of the third nanostructures 32 may be determined suchthat the third meta-surface 432 may diffuse light coming from the secondmeta-surface 422.

FIG. 5 is a side cross-sectional view illustrating a state in which thepropagation direction of light is changed by a light transmitting unit403 according to an example embodiment.

Referring to FIG. 5 , the light transmitting unit 403 may include afirst substrate 443, first meta-surface 413 and second meta-surface 423provided on opposite sides of the first substrate 443, a secondsubstrate 453 provided on the second meta-surface 423, and a thirdmeta-surface 433 provided on the second substrate 453. The firstmeta-surface 413 and the second meta-surface 423 may not face each otherin a direction normal to the first meta-surface 413 and the secondmeta-surface 423 with the first substrate 443 therebetween. The thirdmeta-surface 433 and the second meta-surface 423 may face each other ina direction normal to the second meta-surface 423 and the thirdmeta-surface 433 with the second substrate 453 therebetween. Lightemitted from a light source 203 may be incident on the firstmeta-surface 413. The first meta-surface 413 may deflect the lightemitted from the light source 203 such that the light may have a firstdirectivity. For example, the first meta-surface 413 may refract lightemitted from the light source 203 such that the light may have a firstdirectivity. Light emitted from a plurality of light-emitting elements223 may not be uniformly refracted by the first meta-surface 413. Thefirst directivity may indicate a direction toward a center portion ofthe second meta-surface 423 from a center portion of the firstmeta-surface 413. The direction toward the center portion of the secondmeta-surface 423 may include a direction exactly toward the center ofthe second meta-surface 423 and a direction toward the vicinity of aregion in which the second meta-surface 423 is located. In addition, thefirst meta-surface 413 may collimate the light output from the lightsource 203. Therefore, the light emitted from the light source 203 maypropagate, as parallel light, from the first meta-surface 413 toward thesecond meta-surface 423 through the inside of the first substrate 443.While the light from the light source 203 propagates from the firstmeta-surface 413 to the second meta-surface 423 as described above, thebeam width of the light may be constant. For example, the beam width ofthe light output at the first meta-surface 413 may be equal to the beamwidth of the light incident on the second meta-surface 423.

The light deflected by the first meta-surface 413 may be deflected bythe second meta-surface 423 such that the light may have a seconddirectivity. For example, the second meta-surface 423 may refract thelight output from the first meta-surface 413 such that the light mayhave a second directivity. The degree of refraction of the light may notbe constant at a plurality of points of the first meta-surface 413. Thesecond directivity may indicate a direction toward a center portion ofthe third meta-surface 433 from the center portion of the secondmeta-surface 423. The direction toward the center portion of the thirdmeta-surface 433 may include a direction exactly toward the center ofthe third meta-surface 433 and a direction toward the vicinity of aregion in which the third meta-surface 433 is located. Accordingly, thelight may propagate toward the third meta-surface 433 in a directionnormal to the third meta-surface 433. In addition, the seconddirectivity may be the same as the direction in which light propagatesfrom the light source 203 toward the first meta-surface 413. Inaddition, the second meta-surface 423 may simultaneously refract andcollimate the light output from the first meta-surface 413. Accordingly,the light output from the first meta-surface 413 may be collimated bythe second meta-surface 423, and then the light may proceed toward thethird meta-surface 433 as parallel light.

The light deflected by the second meta-surface 423 may be diffused bythe third meta-surface 433. The light diffused by the third meta-surface433 may be transmitted to an object as flood illumination light.

As described above, the first meta-surface 413, the second meta-surface423, and the third meta-surface 433 may respectively include a pluralityof first nanostructures 13, a plurality of second nanostructures 23, anda plurality of third nanostructures 33. The first nanostructures 13, thesecond nanostructures 23, and the third nanostructures 33 may vary thepropagation direction of incident light depending on factors such as theshape or arrangement of the first nanostructures 13, the secondnanostructures 23, and the third nanostructures 33. For example, theshape distribution of the first nanostructures 13 may be determined suchthat the first meta-surface 413 may refract and collimate light emittedfrom the light source 203. In addition, the shape distribution of thesecond nanostructures 23 may be determined such that the secondmeta-surface 423 may refract and collimate light output from the firstmeta-surface 413. In addition, the shape distribution of the thirdnanostructures 33 may be determined such that the third meta-surface 433may diffuse light output from the second meta-surface 423.

In addition, although the second meta-surface 423 is illustrated asbeing in contact with both the first substrate 443 and the secondsubstrate 453, the second meta-surface 423 is not limited thereto. Forexample, similar to the second meta-surface 421 shown in FIG. 3 , thesecond meta-surface 423 may be provided on the second substrate 453 andspaced apart from the first substrate 443. In this example, a gap may beformed between the second meta-surface 423 and the first substrate 443.In addition, similar to the second meta-surface 422 shown in FIG. 4 ,the second meta-surface 423 may be provided on the first substrate 443and spaced apart from the second substrate 453. In this example, a gapmay be formed between the second meta-surface 423 and the secondsubstrate 453.

FIG. 6 is a view illustrating a simulation of flood illumination by theillumination device 1000 shown in FIG. 1 .

Referring to FIG. 6 , light from the light source 200 may be diffused bythe light transmitting unit 400 and may then be transmitted through thesecond area A2 to illuminate an object as flood illumination light. Thatis, the light transmitting unit 400 may convert light emitted from thelight source 200 into flood illumination light to entirely illuminatethe object at once with a uniform light distribution.

FIG. 7 is a block diagram illustrating a configuration of an electronicapparatus 2000 according to an example embodiment.

Referring to FIG. 7 , the electronic apparatus 2000 may include anillumination device 2100 configured to illuminate an object OBJ withflood light, a sensor 2300 configured to receive light reflected fromthe object OBJ, and a processor 2200 configured to perform an operationto acquire information about the object OBJ from the light that thesensor 2300 has received. The electronic apparatus 2000 may furtherinclude a memory 2400 to store codes and other data for operating theprocessor 2200.

The illumination device 2100 may include a light source, a firstmeta-surface, a second meta-surface, and a third meta-surface, and mayilluminate the object OBJ by changing the distribution of light emittedfrom the light source and transmitting the light toward the object OBJthrough a bezel of a display panel. The illumination device 2100 may beone of the illumination devices of the example embodiments describedwith reference to FIGS. 1 to 5 , a combination thereof, or amodification thereof.

Additional optical devices may be arranged between the illuminationdevice 2100 and the object OBJ to adjust the direction of light L_(FL)emitted from the illumination device 2100 toward the object OBJ oradditionally modulate the light L_(FL).

The illumination device 2100 may illuminate the object OBJ with floodlight L_(FL). The flood light L_(FL) may be light capable ofilluminating the object OBJ entirely at once with a uniform lightdistribution. Uniform light distribution may not be a state of 100%uniformity but a state in which an illumination target region of theobject OBJ is substantially uniformly illuminated. Specific structuresof the first meta-surface, the second meta-surface, and the thirdmeta-surface, that is, the shape distribution of nanostructures providedon the first meta-surface, the second meta-surface, and the thirdmeta-surface may be determined to obtain a desired uniformitydistribution of flood light L_(FL) according to the position and shapeof the object OBJ. The object OBJ may be the face of a user of theelectronic apparatus 2000. The position of the object OBJ may be about30 cm to about 1 m away from the illuminating device 2100, but is notlimited thereto.

The sensor 2300 senses light L_(r) reflected from the object OBJ. Thesensor 2300 may include an array of light detecting elements. The sensor2300 may further include a spectroscopic element to analyze light L_(r)reflected from the object OBJ according to wavelengths of the lightL_(r).

The processor 2200 may perform an operation using light detected by thesensor 2300 to obtain information about the object OBJ. In addition, theprocessor 2200 may be responsible for all processing and controllingoperations of the electronic apparatus 2000. The processor 2200 mayacquire information about the object, for example, may acquire andprocess two-dimensional or three-dimensional image information about theobject OBJ. In addition, the processor 2200 may control overalloperations such as the operation of the light source of the illuminationdevice 2100 or the operation of the sensor 2300. In addition, theprocessor 2200 may also determine whether to authenticate a user basedon information acquired from the object OBJ, or may execute otherapplications.

The memory 2400 may store codes to be executed on the processor 2200. Inaddition to this, the memory 2400 may store various execution modules tobe executed on the electronic apparatus 2000, and data for the executionof the various execution modules. For example, the memory 2400 may storea program code to be used when the processor 2200 performs an operationfor acquiring information about the object OBJ, and codes such asapplication modules to be executed using the information about theobject OBJ. In addition, the electronic apparatus 2000 may includeadditional devices, and the memory 2400 may further store programs suchas a communication module, a camera module, a video replay module, or anaudio replay module for operating the additional devices.

Results of calculation of the processor 2200, that is, information aboutthe shape and position of the object OBJ may be transmitted to anotherdevice or unit if necessary. For example, information about the objectOBJ may be transmitted to a controller of another electronic apparatusthat uses the information about the object OBJ. The other device or unitto which results of calculation of the processor 2200 are transmittedmay be a display device or a printer capable of outputting the results.The other device or unit may be, but is not limited thereto, asmartphone, a cellular phone, a personal digital assistant (PDA), alaptop, a personal computer (PC), a wearable device, a mobile device, ora non-mobile computing device.

The memory 2400 may include at least one type of recording mediumselected from the group consisting of a flash memory, a hard disk, amicro multimedia card, a memory card (e.g., a secure digital (SD) cardor an extreme digital (XD) card), a random access memory (RAM), a staticrandom access memory (SRAM), a read-only memory (ROM), an electricallyerasable programmable read-only memory (EEPROM), a programmableread-only memory (PROM), a magnetic memory, a magnetic disk, and anoptical disk.

For example, the electronic apparatus 2000 may be, but is not limitedthereto, a portable mobile communication device, a smartphone, a smartwatch, a PDA, a laptop, a PC, a mobile computing device, or a non-mobilecomputing device. The electronic apparatus 2000 may be an autonomousdevice such as an unmanned vehicle, an autonomous vehicle, a robot, or adrone, or may be an Internet of things (IoT) device.

FIG. 8 is a perspective view illustrating an example appearance of theelectronic apparatus 2000 shown in FIG. 7 .

Referring to FIG. 8 , the electronic apparatus 2000 may include a fullscreen display. That is, a display surface 2100 a may occupysubstantially the entire region of the front surface of the electronicapparatus 2000, and a bezel 2100 b which is an edge portion of theelectronic apparatus 2000 may be very narrow. In addition, the displaysurface 2100 a may have a rectangular shape without a notch.

Any one of the illumination devices described with reference to FIGS. 1to 6 may be provided in the electronic apparatus 2000 such that floodlight may be output through the bezel 2100 b of the electronic apparatus2000. The flood light output through the bezel 2100 b may be used toilluminate an object located outside the electronic apparatus 2000. Inthis manner, light having image information may be output through thedisplay surface 2100 a, and light for illuminating an object may beoutput through the bezel 2100 b. As described above, the bezel 2100 b onwhich images are not displayed is used as a region for dischargingobject illumination light, and thus the spatial efficiency of theelectronic apparatus 2000 may be increased. That is, since a space foremitting object illumination light is not additionally required, thesize of the electronic apparatus 2000 may be reduced.

FIG. 9 is a flowchart illustrating an illumination method according toan example embodiment.

Referring to FIG. 9 , the illumination method may be performed using anillumination device which includes a window panel having a first areaand a second area, and a light source provided on a lower side of thewindow panel. The illumination method may include a first lightdirection changing operation in which light emitted from the lightsource is refracted toward the second area of the window panel (S101), asecond light direction changing operation in which the light reaching alower side of the second area of the window panel is refracted andcollimated such that the light may propagate perpendicularly toward alower surface of the window panel (S102), and a flood illuminationproviding operation in which the light reaching the lower surface of thewindow panel is diffused (S103).

In the first light direction changing operation S101, light emitted fromthe light source, which is located at a position does not face thesecond area of the window panel in a direction normal to the windowpanel, may be transmitted to a lower side of the second area of thewindow panel. Based on operation S101, light emitted from the lightsource, which is not located to face the second area of the window panelin a direction normal to the window panel because of design limitations,may reach the second area of the window panel. In the first lightdirection changing operation S101, light emitted from the light sourcemay be refracted to change the propagation direction of the light.Furthermore, in the first light direction changing operation S101, thelight emitted from the light source may be collimated to provideparallel light.

In the second light direction changing operation S102, the lightpropagating at an arbitrary angle toward the lower side of the secondarea of the window panel may be directed such that the light maypropagate perpendicularly toward the window panel. Thus, light emittedfrom the light source may be incident on a lower surface of the secondarea of the window panel at a direction normal to the lower surface ofthe second area of the window panel. In the second light directionchanging operation S102, the light from the light source may berefracted to change the propagation direction of the light. Furthermore,in the second light direction changing operation S102, the light fromthe light source may be collimated to provide parallel light.

In the flood illumination providing operation S103, the light reachingthe lower surface of the second area of the window panel may bediffused. As the light is diffused as described above, uniform floodlight may be provided.

Light emitted from the light source that does not face the second areaof the window panel in a direction normal to the second area of thewindow panel may be directed to the second area of the window panel bythe above-described illumination method. Furthermore, flood light may beoutput through the second area of the window panel. Due to designlimitations, the light source may not be arranged to face the secondarea of the window panel in a direction normal to the second area of thewindow panel which corresponds to a bezel. In this example, lightemitted from the light source may be output through the bezel as floodlight by using the above-described illumination method according to anexample embodiment.

Light emitted from a light source located on a rear side of a displaypanel may be output through an edge portion of a display surface of anelectronic apparatus by using the above-described illumination deviceand the illumination method.

Therefore, a light source may be more effectively arranged for varioussensors without affecting the size of a display surface of a displaypanel.

The operations described in the example embodiments which are notintended to limit the scope of the present disclosure. For simplicity ofdescription, electronic configurations, control systems, and software ofthe related art, and other functional aspects of the systems may not bedescribed. Furthermore, line connections or connection members betweenelements depicted in the drawings represent functional connectionsand/or physical or circuit connections by way of example, and in actualapplications, they may be replaced or embodied as various additionalfunctional connections, physical connections, or circuit connections.

It should be understood that example embodiments described herein shouldbe considered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each exampleembodiment should typically be considered as available for other similarfeatures or aspects in other embodiments.

While example embodiments have been described with reference to thefigures, it will be understood by those of ordinary skill in the artthat various changes in form and details may be made therein withoutdeparting from the spirit and scope as defined by the following claims.

What is claimed is:
 1. An illumination device comprising: a displaypanel configured to output light comprising image information; a lightsource configured to emit light, the light source being spaced apartfrom the display panel; a window panel comprising a first areaconfigured to transmit the light output from the display panel and asecond area configured to transmit the light emitted from the lightsource; and a light transmitting unit configured to transmit the lightemitted from the light source to an object through the second area, thelight transmitting unit comprising at least one meta-surface.
 2. Theillumination device of claim 1, wherein the light transmitting unit isprovided between the window panel and the light source.
 3. Theillumination device of claim 1, wherein the at least one meta-surface ofthe light transmitting unit comprises: a first meta-surface configuredto deflect the light emitted from the light source such that the lightdeflected by the first meta-surface has a first directivity; a secondmeta-surface configured to deflect the light deflected by the firstmeta-surface and having the first directivity such that the lightdeflected by the second meta-surface has a second directivity that isdifferent from the first directivity; and a third meta-surfaceconfigured to diffuse the light deflected by the second meta-surface. 4.The illumination device of claim 3, wherein a center portion of thesecond meta-surface and a center portion of the third meta-surface facethe second area in a direction normal to the second area.
 5. Theillumination device of claim 4, wherein a center portion of the firstmeta-surface is closer to the display panel than the center portion ofthe second meta-surface is to the display panel.
 6. The illuminationdevice of claim 5, wherein the first directivity corresponds to adirection from the center portion of the first meta-surface toward thecenter portion of the second meta-surface.
 7. The illumination device ofclaim 5, wherein the second directivity corresponds to a direction fromthe center portion of the second meta-surface toward the center portionof the third meta-surface.
 8. The illumination device of claim 5,wherein the second directivity is equal to a direction in which thelight emitted from the light source propagates toward the firstmeta-surface.
 9. The illumination device of claim 3, wherein the lighttransmitting unit further comprises a first substrate provided betweenthe first meta-surface and the second meta-surface, and a secondsubstrate provided between the second meta-surface and the thirdmeta-surface.
 10. The illumination device of claim 3, wherein the firstmeta-surface comprises: a plurality of first nanostructures having ashape dimension which is less than a wavelength of the light emittedfrom the light source.
 11. The illumination device of claim 10, whereinthe first meta-surface is configured to collimate the light emitted fromthe light source based on a shape and a distribution of each of theplurality of first nanostructures.
 12. The illumination device of claim3, wherein the second meta-surface comprises a plurality of secondnanostructures having a shape dimension which is less than a wavelengthof the light from the light source.
 13. The illumination device of claim12, wherein the second meta-surface is configured to collimate the lightoutput from the first meta-surface based on a shape and a distributionof each of the plurality of second nanostructures.
 14. The illuminationdevice of claim 3, wherein the third meta-surface comprises a pluralityof third nanostructures having a shape dimension which is less than awavelength of the light from the light source.
 15. The illuminationdevice of claim 14, wherein the third meta-surface is configured todiffuse and transmit the light output from the second meta-surface toradiate the object with flood illumination based on a shape and adistribution of each of the plurality of third nanostructures.
 16. Theillumination device of claim 15, wherein the flood illumination has afield of view of 80 degrees.
 17. The illumination device of claim 1,wherein the light source comprises a plurality of light-emittingelements.
 18. The illumination device of claim 17, wherein each of theplurality of light-emitting elements comprises a vertical cavity surfaceemitting laser.
 19. The illumination device of claim 1, furthercomprising: a support substrate provided on a lower side of the lightsource opposite to the light transmitting unit; a plurality of supportportions provided between the support substrate and the lighttransmitting unit and configured to provide a space in which the lightsource is provided; and a housing surrounding the window panel, thelight transmitting unit, the support substrate, and the plurality ofsupport portions.
 20. An electronic apparatus comprising: anillumination device comprising: a display panel configured to outputlight comprising image information; a light source configured to emitlight, the light source being spaced apart from the display panel; awindow panel comprising a first area configured to transmit the lightoutput from the display panel and a second area configured to transmitthe light emitted from the light source; and a light transmitting unitconfigured to transmit the light emitted from the light source to anobject through the second area, the light transmitting unit comprisingat least one meta-surface; and a sensor configured to receive lightreflected from the object; and a processor configured to acquireinformation about the object based on the light received by the sensor.